import java.util.ArrayList;

public class MyStack {

    private ArrayList<Object> arrayList;

    public MyStack() {
        arrayList = new ArrayList<>();
    }

    public void pop(Object o) {
        arrayList.add(o);
    }

    public Object myRamove() {
        int size = arrayList.size();
        if (size > 0) {
            return arrayList.remove(arrayList.size() - 1);
        }else {
            return -1;
        }
    }
    public int getSize() {
        return arrayList.size();
    }

}